7. Acute Radiation Sickness Is Possible
While chronic exposure raises long-term risks, a powerful solar storm could pose immediate danger to astronauts on Mars. If caught outside protective shelter during a major solar particle event, radiation doses could reach levels known to trigger acute radiation sickness—including symptoms like nausea, fatigue, and more severe effects. Johns Hopkins Medicine highlights that even brief, high doses are hazardous if shielding is inadequate.